In this elegant comedy of manners, Penelope O'Farrell discovers that her husband has been having an affair with an attractive married woman. Instead of lapsing into despair, she decides to employ some cunning strategies to save her marriage.

After many years living abroad with her longtime lover, Lady Catherine Champion-Cheney visits her former marital home, now occupied by her son, Arnold, and his wife, Elizabeth. Also present is her estranged husband, Clive, who lives in a cottage on the estate. Elizabeth has become dissatisfied with the life she leads with her wealthy husband, who is very occupied with his political career, and she encourages the advances of a dashing but impecunious suitor, Teddy Luton.